I am a mechanical engineer. A portion of my career has been the engineering of light bulbs. The physics and chemistry of light bulbs and their manufacture are deep and broad. Some points to address the article and the numerous comments:

For those inclined to do the math for gas-filled incandescent bulbs: The equation (V/V0)^1.84 = E/E0 describes how the Efficacy (lumens per watt) varies with voltage. For life (using L/L0 in the right hand side of the equation instead of E/E0), the exponent in the left hand side of the equation is -13.1. For lumens, the exponenet is 3.38. For watts, 1.54. For Amps, 0.541. If you change the technology (say, to halogen), then all of these exponents change.

The theoretical maximum efficacy for a source that emits only pure white light (no IR, no UV, a CRI of 100,and a color temperature of 6500K) is 273 lumens per watt. Making a white light source with those properties is impossible. Can't even come close. The human eye is most sensitive to light at 555 nanometers (green). The theoretical maximum for monochromatic light at 555 nm is 680 lpw. The ugly yellow low-pressure sodium parking lot lights are the most efficient lighting available, at about 300 lpw. Fluorescent bulbs can achieve about 85 lpw.

Only very small incandescent bulbs (example: a car's dashboard light) have a vacuum inside. All others have a mix of nitrogen (to suppress arcing) and a noble gas (either argon, krypton, or xenon). The bulbs "pop" when you drop them because the pressure inside is slightly lower than atmospheric pressure when the bulb is cold. When the bulb is warm, the pressure inside and out are nearly equal.

Please note: LED lights are electronic circuits. If the solder is lead-based, then you end up introducing lead into the environment. Lead-free solders exist, but, of course, are more expensive. Every form of lighting produces some kind of undesriable side effect. We may debate over which is the least harmful overall, but let's not pretend any of the lighting technologies is completely eco-friendly.

LEDs for residential lighting has a long way to go yet. To be fair, the fact that white LEDs produce a false white needs to be balanced by the fact that all fluorescent bulbs also produce a false white.

Nearly every bulb in my house is a CFL (made the full-household switch four years ago, though I have been using CFLs for for some lighting for 20 years). In the past 4 years, only one failed prematurely. The warm-up time is about a minute, and you get used to it. There is light immediately (about 50% of full lumens), so there is always enough light output to get across a room without tripping.

There is very little mercury in a CFL. And if you buy a CFL that uses an amalgam (a solid mercury alloy) instead of liquid mercury, it becomes even easier to minimize the amount of mercury that gets into the environment.

Regarding the "cheap Chinese junk" commentary, I agree that it is not a useful statement. That said, there is a very large range of quality in CFLs, so it requires a much more light-educated consumer to buy CFLs than incandescents. My personal favorite is Philips. (No, I have never worked for Philips. I used to work for their competitor, GE Lighting.)

Saying that the color spectra of CFLs is "terrible" is relative. Some CFLs do have lousy color. You have to shop around. A CRI of at least 80 is perfectly acceptable in a residence, and some 90 CRI CFLs are available.

@ Leon HAHA
I think we agree that the industrial revolution was a great thing, and I for one am thrilled that my forefathers (I'm an engineer too) did such an efficient job of turning so much coal into CO2. That was 1865.
My point though, in 2011, is that just making lighting more efficent will simply encourage (incentivise, if you will) people to leave lights on more, and light up the exterior of their houses more, build hotels with more lighting, and city parks will be better lit as well. There is no incentive to use less energy. This view of the future is based on Tsao's actual research, not my opinion. It's hard to guess at the future while ignoring this type of unbiased research of the past.
The purported mandate for the CFLs is to save energy. It won't happen. The mandates for CFLs will not reduce energy consumption, but increase it. My guess the electric companies know this; I'm not paranoid, but don't they read the Economist too? So it's a boondoggle posing as true legislation to solve problems.
We agree the politicians are rational, if using the definition of rational to be "seeking one's own personal self-interest in the near term". But in this instance I mean rational to mean "to seek to perform your job to the best of your ability, over the long term". The politicians are elected to act in the nation's best interest. I can't see anyone agreeing our nation is better served by encouraging people to use more lights.
It's great that we technical people develop these lights on our own dime. The lighting industry competition is great too. But I'd like the government to stay out, except to levy as few taxes as needed to operate. Since energy use is pervasive, and the rich use more than the poor, taxing (ALL) energy uniformly would be progressive. But such a new tax system requires lots of leadership. We have precious little of that.

Firstly, I hazard to guess all those efficient steam engines were not simply let to run idly and purposelessly. Instead, together they probably powered this thing called the industrial revolution which culminated in today's climax of you and I, perhaps a world apart, busy punching away on our keyboards to discuss the relative merits of such- a darn miracle if you ask me.

Secondly, try to make people use energy more efficiently, as legislation on efficient light bulbs would, has a much higher chance of success than try to make people stop using energy, as your taxes would. It's for the very same reason seatbelts/airbags laws were passed and not the heavier petrol tax to reduce overall use of vehicles, and thus accidents. Contrary to what you believe, I think our politicians are every bit as rational as you and I, if not more. Going around telling people they need to turn the lights off or watch less TV or get ready to pay is political suicide few politicians will commit, and who can blame them?

It is clear from this 150 years' of research that, as energy using devices are made more efficient, per capita energy use increases, not decreases. In 1865 Jevon showed that coal use increased as steam engines became more efficient, since the engines needed less tending and could apply to more and more applications. The increased energy use is caused by the sheer convenience of getting value from highly efficient steam engines, automobiles, and all types of refrigeration. In 2010 Tsao proved the idea applies to lighting.
This is all well researched, hence the government mandates for efficient lighting are not for environmental reasons, but must be for the gain of some other special interest group. To reduce energy use by the consumers and to encourage new technical developments of higher efficiency devices, even a child would observe that one could merely tax energy use. An even wiser child would suggest that the increased tax be phased in over a predictable period to allow time for rational consumers and businesses to plan and respond.
Ahh, you reply, this is rational but not practical politics. Yes, practical politics have certainly become irrational. Can this explain why we have irrational people attracted to politics, eh?

@I am rather bemused by the people who point out that the heat emitted by lights isn't really waste energy. It adds to building heating. As if we didn't know that!
This is pointed out by several posters here and in letters in response to most other articles I have seen on the subject.
Well, thank you for stating the bleeding obvious but not all of us live in cold climates. I live in a place where the temperature is usually well into the 30s and only very occasionally dips into the mid-20s. The air conditioning is usually running and every joule of additional thermal load is a direct air conditioning cost.
I am sure that this is the case in many countries.
I like to read and I use a personal reading lamp on the headboard of my bed. Since I installed a compact fluorescent lamp I have found it to be much more comfortable not to have my left ear toasted by an incandescent. It's not cold. But it is noticeably cooler. I can touch the lamp for a few seconds with my bare fingers. Doing that with an incandescent would result in blisters.

Its pretty amazing to see that even today there are a significant number of people who believe that "Minimizing energy use seems an odd thing to aim for". While I understand that affording electricity is not a problem is most of the developed countries, I don't think a lot of them understand how the lack of it is affecting people in developing countries.
The conservation of power / energy actually seems more important in developed countries where people don't seem to care for wastage at all. I see so many buildings and stores which leave all the lights on all night just to advertise their place. I mean the sheer arrogance there is surprising and shocking.
It's not too far away when shortages in power/energy sector will start forcing people everywhere (even in developed countries) to review their attitude towards minimizing energy consumption. In the same way as people started switching from gas guzzlers to 35 - 40 miles per gallon cars.

Fluorescents, and especially the CFL bulbs, give me a headache due to flicker.

As others have mentioned, they also have absolutely terrible color spectra. The only light source that's worse, in my subjective opinion, is those yellow sodium streetlights.

I haven't seen any LED bulbs yet, aside from cheap keychain flashlights, but from what I hear, their lifespans are pretty short. These are not the cheap red ones used in Radio Shack electronics projects, which do last seemingly forever. Like embryonic stem cells vs. autotransplanted adult stem cells (every disease cure I've read about has come from adult stem cells; the abortion lobby and researchers pretend that embryonic stem cells are the cure for everything, when in fact they create the same transplant-rejection problems that any other foreign tissue does), the media has, apparently, intentionally muddled the debate in order to support the left's political position.

Interference by the government in my choice of lighting could only be defended if the products forced onto me perform just as well as the ones being outlawed. Whatever those expensive government campaigns may try to make you believe, this is not the case.

When it comes to the quality of light in terms of evenly covering the full colour spectrum (like sunlight), only incandescent/halogen lamps perform close to a CRI of 100% (Colour Rendering Index). CFL and LED don't even come close. Fluorescent light for instance, is too low in red light (adding red would increase energy usage). A simple test is to compare the colour of the skin of your hand under a CFL and an incandescent lamp. Or just ask any musuem director what sort of lamps they need for bringing out the true colours of their paintings.

If its "cheap Chinese junk" I wonder why you'd have to hide your own name. Is it because you're afraid that the readers would find out that your actual identity isn't that of a well known economics writer but actually a 20-25 year old intern? Come on, no "statistics" about "cheap Chinese junk". Uninformative, garbage article.

In principle, I am a proponent of alternatives to incandescent light bulbs. However, they are generally QUITE expensive compared to the incandescents, and at least the early ones I bought didn't last long by anybody's standards, much less live up to the hype of 10 - 15 years! So I'm reluctant to buying anything at all, unless I have to; and if I'm renting, and don't want to be worried about packing and shipping light bulbs, I'm doubly reluctant.

With respect to mercury: From what I've read, there isn't very much of it in CFLs.

With respect to heat: LEDs are not stone-cold, because they still dissipate power, and all that power eventually becomes heat. However, a lot more of it becomes light first in the case of the LEDs, whereas only 2% of an incandescent's power even starts out as light. So to get the same amount of light, an incandescent has to start out with, and thus consume, a lot more power.

Is a definition of an urban myth that it is believed by conspiracy theorists despite unarguable facts? Patents are published (in fact, patent applications are published before they have even been looked at) and are available for everyone so that the idea which has been protected, the idea has to be reasonably completely explained, and the monopoly granted, are made public. This protection only lasts for (mostly) 20 years, then people can do what they like with the idea. So the idea that someone can bury a patent by buying it is absurd. Otherwise you'd simply have to keep it secret. Which is not a patent. C'est patent!

The debate on new lighting techniques in Britain has passed the point of absurd, at least in the popular press, who appear to see a huge (usually Brussels-based) conspiracy to attack our hard won rights to waste energy as we please. I simply can't see why people prefer fussy, fragile and inefficient bulbs over LEDs. Old-fashioned bulbs don't even heat efficiently. Good riddance to 'em. Still, it seems that 12/13 years of compulsory education in Britain still can't win over the Luddites or the lazy, or get journos to master their facts.

However, as a matter of policy I do think that it is the role of government(s) to set new standards that provoke new technologies, greater efficiency and, with a bit of luck, reductions in use of finite energy resources and investigations into "infinite" resources. Governments also need to ensure a free market place to allow these ideas to develop. Of course we need the energy from somewhere, but I'd also like to have a nice, clean and efficient - and well-lit - world to live in.

A few thoughts. First, the total energy consumed in a bulb's lifetime - including manufacture and transport - should be taken into account. Second, heat is not lost - take Canada, where six months a year, the temperature is below freezing.

Third, and most fundamentally: what gives governments the right? I am quite sure it would save energy if we all wore a green suit. Or if we all stopped playing sports and watching cinema movies. Or taking vacations. Or if we stopped reading magazines, such as you newspaper, which I am quite sure consumes more energy and trees than the bulbs in my home. Consuming energy is what we DO. We move, we live, we travel, we create art, we make choices. Minimizing energy use seems an odd thing to aim for. Whenever governments start to engage in such social engineering, failure or misery results: usually both.

Hi,
Illumination.The incandescent light bulb has given light to many a dark moment and on the seventh day gave light. However conspiracy theories in and around the Al Gore concerts incandescent light bulb fell out of fashion and from September 2009 should not be sold and replaced by more efficient CLF types. These efficient types are especially good for the blind as they take some time to light up when switch on. The could be a conspiracy theories to make damage when you enter a dark room. However "all is not well in the state of Denmark", toxic effect and waste disposal problems with CLF bulbs arise (toxic mercury, ultraviolet radiation, and electromagnetic fields).
Regards Dr. Terence Hale

"By contrast, the bulb’s lifespan is inversely proportional to the voltage raised to the power 16." Are you sure about that? I worked with a bulb manufacturer on aircraft warning lights for tall structures. They told me the bulb life varied with the 5th power of voltage.

I'm waiting for good, affordable LED lighting. Unfortunately I'm gonna be stuck with all these long-lasting CFLs I've gotten in the meantime. God help you if one of them breaks, I've tried to find out how to legally dispose of it, and there simply isn't the information out there. The U.S. government guidelines tell you to check state laws, and the state laws are incomplete (some say to throw it in the regular trash, but I know for a fact my regular trash gets incinerated, is this REALLY what they want me to do with it?)
Meanwhile I've got 2 young kids, and am far from certain that I properly got rid of the mercury vapor which leaks from a broken CFL. Rarely do I come down on the side of the republicans, but until we have a safe alternative (I.E. good LED lights), I find it strange to even encourage the sale of these things. I make a concerted effort not to bring poison into my home, avoiding things like incecticides, and though I do use mercury vapor filled bulbs, I think that is a choice for the consumer to make for themselves.

Good article and good comments, though I do have to play devil's advocate for the tungsten filament bulb before it (rightly) becomes an archaeological relic:

The helical filament you can just about see with the naked eye is only the tip of the iceberg so to speak. The 'filament' of which this visible helix consists is itself a helix of tungsten wire - just too small to see. Furthermore, tungsten is naturally rather brittle so the processes involved in producing such a fine helix-in-a-helix are fairly involved. Finally, the filament itself is enclosed in a vacuum to stop it oxidising. You get all this and other remarkable feats of engineering for a few pence when you buy a bulb from the supermarket which I think is rather incredible.

Also worth noting is that the 'lost' heat is not necessarily pure waste. In a room in a hot country where air conditioning is being run at the same time as incandescent bulbs then the inefficiency is obviously amplified. In a cold country where heating is being run at the same time as incandescent bulbs then the heat is not really being lost at all: if LED lights were used instead, the heating would have to be working harder to maintain the same room temperature. I realise that light bulbs and household heaters aren't the same thing, but luminous efficacy alone is a somewhat crude yardstick at times.

Lighting-grade LEDs are anything but "stone-cold". Put your hand in front of a powerful LED and the heat caused by the light is quite palpable.

Furthermore, "power" LEDs eject excess heat in the opposite direction of the emitted light, requiring more complicated heat sinking than with traditional bulbs which project heat in the same direction as the light.

Finally, white LEDs do not emit an evenly distributed spectrum, making them inappropriate for high quality colour reproduction, and they require efficiency reducing coatings to shift their glaringly white light down to a more pleasant colour temperature.

So while I personally find the promise and recent technical progress of this type of "solid state lighting" absolutely amazing, the technology is not without problems as a replacement technology for incandescents.

CFL light bulbs may be far more energy-efficient than the traditional tungsten-filament sort, but they are hardly the answer to all environmental questions. They contain mercury and inevitably they will break sometimes; mercury vapour is really toxic. People who work in the plants where they are made have quite severe health problems.

So far as I know, LED light bulbs don't have any of that sort of problem.